1. Nucleus: Z = # protons = 1 for hydrogen to 94 for plutonium N = # neutrons Atomic mass A ≈ Z + N BOHR ATOM CHAPTER 2: ATOMIC STRUCTURE AND INTERATOMIC BONDING

2. WAVE-MECHANICAL ATOM

3. have discrete energy states tend to occupy lowest available energy state. Electrons... ELECTRON ENERGY STATES

4. Electron Configuration

6. Columns: Similar Valence Structure Electropositive elements: Readily give up electrons to become + ions. Electronegative elements: Readily acquire electrons to become - ions. THE PERIODIC TABLE

7. Example: NaCl IONIC BONDING

8. Predominant bonding in Ceramics Give up electronsAcquire electrons EXAMPLES: IONIC BONDING

9. Example: CH 4 C: has 4 valence e, needs 4 more H: has 1 valence e, needs 1 more Electronegativities are comparable. COVALENT BONDING

10. Molecules with nonmetals Molecules with metals and nonmetals Elemental solids (RHS of Periodic Table) Compound solids (about column IVA) EXAMPLES: COVALENT BONDING

11. Primary bond for metals and their alloys METALLIC BONDING

12. Fluctuating dipoles SECONDARY BONDING

13. Ceramics (Covalent & Ionic bonding): Metals (Metallic bonding): Polymers (Covalent & Secondary): Large bond energy large T m large E small  Variable bond energy moderate T m moderate E moderate  Directional Properties Secondary bonding dominates small T small E large  SUMMARY: PRIMARY BONDS